Mechanisms for clamping gravure plates are well known. Illustrative of this is German Offenlegungsschrift No. 2,804,304 which discloses toggle levers to actuate a plate-clamping mechanism. Also illustrative of prior art plate-clamping mechanisms is U.S. Pat. No. 2,157,621 to Neilson which discloses a printing cylinder having a peripheral cavity forming a channel along the cylinder's longitudinal length. In the cavity, a cylindrical bearing having an edge portion to receive one end of a printing plate is rotated so as to tension and clamp the printing plate onto the printing cylinder. However, the Neilson mechanism is unsuitable for clamping plates of different thicknesses or for use in connection with an inclined cylinder cavity (i.e., the longitudinal axis of the cavity skewed from the cylinder's axis of rotation).
Traditionally, in a plate-clamping mechanism with an inclined cylinder cavity, the mechanism's axis of rotation is parallel to the cylinder's axis of rotation. Accordingly, the plate-clamping mechanism, when opened and considered over its length, projects from the cylinder cavity and above the cylinder surface on one side while remaining below the cylinder surface on the opposite side. Because of this prior art arrangement, it is often difficult to clamp the printing plate to the cylinder without leaving a gap between the plate's end and the cylinder's surface. This is especially a problem for plates of significant thickness and reduced flexibility.